By HOWARD FENDRICH Roger Clemens' former personal trainer Brian McNamee was meeting Friday with federal prosecutors building a perjury case against the seven-time Cy Young Award winner.McNamee arrived at the U.S. Attorney's office in Washington accompanied by his lawyers, Richard Emery and Earl Ward. Asked by a reporter if he wanted to comment on the way into the building, McNamee shook his head no.He has told federal agents and baseball investigator George Mitchell he injected Clemens more than a dozen times with steroids and human growth hormone from 1998-01.